Chair for use in x-ray photographing of teeth



Oct. 14, 1952 Y. v. PAATERO 2,613,726

CHAIR FOR USE IN X-RAY PHOTOGRAPHI-NG OF TEETH Filed Feb. 27,1948 2 smaw-smsw 1 YRITb \Yuz FAATE R0 INVENTQIR W ATTORNEY.

Oct. 14, 1952 Y. v. PAATERO 2,613,726

CHAIR FOR USE IN X-RAY PHOTOGRAPHING OF TEETH Filed Feb. 2'7, 1948 2 SHEETSSHEET 2 TEE-EYE- YRzr VELI PAATERO INVENTOR BY W ' ATTORNEY Patented Oct. 14, 1952 CHAIR FOR USE IN X-RAY PHOTOGRAPHING OF TEETH Yrjii Veli Paatero, Helsinki, Finland Application February 27, 1948, Serial No. 11,545

In Finland, March 19, 1947 2 Claims. 1

This invention relates to chairs adapted for use in X-ray photographing of teeth.

On employing the method described in my prior application Ser. No. 723,764, filed January 23, 1947, which has become abandoned and which relates to allowing a fan of rays to pass evenly along the dental arc to a film of suitable size and form extending from the one endv of the dental arc to the other in such a way that this fan of rays is always perpendicular to the alveolar process, either the X-ray direction tube set forth in said application can be passed, as mentioned, along the row of teeth or e. g. the chair of the patient can be moved in respect to the direction tube. For the last mentioned purpose the inventor has designed for the patient a chair which moves when the radiogram is being taken, in the manner corresponding to the dental arc. The chair can be constructed so that it can be either utilized separately in connection with any X-ray apparatus, or coupled originally to the X-ray apparatus frame.

The chair according to the present invention is characterized thereby, that it is provided with means for placing the patient into a specified position in regard to both the rotation axis of the chair and the X-ray source and means for moving the seat at first linearly a specified distance, then in an arc of about 130 around the vertical axis and finally linearly again. According to an embodiment the back of the chair for this purpose is provided with a neck support adjustable vertically and horizontally and also a skull cap adjustable vertically and horizontally and a flexibly joined, arclike arm which indicates the position of the rotation axis in the patients mouth. The means for moving the seat consists of a bottom plate fixed e. g. to the foot of the chair and provided with guide grooves, a slide plate fixed to the seat and superposed on said bottom plate and provided on the under side with pins running in said guide grooves and a gear co-acting with the toothed edge of said slide plate. The gear can be rotated indifferent ways e. g. by means of a hand crank or an elec tric motor. The slide plate pins and the bottom plate guide grooves corresponding to said pins are arranged so that the two extreme pins can rotate around the central one and that further all the three pins can move linearly still retaining their mutual positions unchanged. Thus, the middle groove is straight, the foremost groove is straight at its ends and forms an arc in the middle and the rearmost groove forms an arc the ends of which are connected with a straight part.

The centre of the middle groove is also the centre 2 of both arc-like groove parts and thus coincides with the vertical axis of the chair.

The annexed drawings illustrate an embodiment of the chair according to this invention and means for operating said chair.

Fig. 1 is a side view of the chair equipped with means for placing and fixing the patients head into a specified position in regard to the X-ray source.

Fig. 2 illustrates the guide plate under the seat and the toothed slide plate as viewed from under.

Fig. 3 illustrates the same as Fig. 2 when the seat is turned sidewards.

Before taking the X-ray picture the patient in the chair must be placed into a specified posi tion in regard to the vertical axis in order that the movement of the chair corresponds acourately to the curvature of the teeth row and that the X-rays be perpendicular to the alveolar process (lat. processus alveolaris). Accordingly, to obtain on an average a suitable direction angle of the central beam for each group of teeth the patients head is inclined slightly forward when the upper teeth are'radiographed and, on the contrary, slightly backward when the lower teeth are radiographed. When the beam director is in addition adjusted so as to form a definite anglewith the horizontal plane, the correct vertical direction of the central beam is obtained.

The seat I of the chair on pedestal 2 rotates around a vertical axis 3. The imaginary extension of said axis is denoted by reference number 3a. The upper part of back 4 is provided with a neck support 5 which is adjustable both ver tically and horizontally as indicated by arrows. The neck support 5 is mounted on bracket 2| which terminates in a collar or sleeve 22 encircling the back member 4. Set screw 23, which is adjustable, secures the collar or sleeve 22, and the neck support 5 carried thereby, to the back 4. The skull cap 6 is arranged above said neck support and can also be adjusted vertically and horizontally. The skull cap 6 is supported on bracket 24, this bracket terminating in collar or sleeve 25, which is adjustably secured to the back 4 by means of the set screw 26.

Moreover the back is provided with an arclike arm I flexibly joined thereto and when said arm is lowered it indicates the position of the imaginary extension of the axis 3a in the patients mouth. The patients head is placed in the correct position as regards indicator 8 on said arm, said arm is removed and the direction tube of the X-ray apparatus is adjusted in its place. When the chair is then turned, by turning crank l7, either by hand, or by means of an electric motor,

, 3 thereby rotating th shaft 3| to which the crank I1 is operatively connected, and thereby causing the gear I6, which is connected to the shaft 3|, also to rotate, the X-rays always fall perpendicularly to the processus alveolaris and the teeth row.

The seat is moved by means e. g. illustrated in Fig. 2. Bottom plate 9 is fixed to pedestal 2. Slide plate I0 is superposed on said bottom plate and fixed to seat I. The under surface of slide plate I0 is equipped with pins 32), I I and I2 which run in grooves I3, I4, and I5 provided in bottom plate 9. The edge of slide plate It) is toothed, these teeth 33 meshing with the teeth on the gear I6, thus causing the slide plate IO to rotate upon rotation of the gear I5 arranged in bottom plate 9. When gear I6 is operated by means of a motor or manually, by means of crank II, through shaft 3| and gear I6, which meshes with the teeth 33 on the edge of slide plate III, as previously described the edge of slide plate I0 turns with said gear as guided by pins 322, II and I2. Aslong as pins I I and I2 move in an arc and pin 3b remains stationary, the seat also turns in an arc of about 130. The pins 317, II and I2 then move linearly sidewards about 5 cm. and seat I thus follows the shape of the teeth row.

The means set forth in this invention can be constructed in many different ways without deviating from the scope and spirit of this invention. Specific parts of the chair can be made exchangeable so that the chair can also be used for children. The gear can be constructed for several different shapes of mouth so that a simple coupling makes it possible to turn the chair in 2,.

different ways. Friction between bottom plate 9 and slide plate I!) must be as small as possible and plate material must be chosen accordingly.

I claim:

l. A dental X-ray chair having means for motion about the vertical axis thereof, said chair having a patients seat, means for arcuately moving said seat. whereby to conform to the arcuate contour of the processus alveolaris, said chair also including a pedestal support, a bottom plate fixed to said pedestal support, a, slide plate superposed on said bottom plate and fixed to said seat, said seat being mounted on said pedestal support, and means for moving said seat at first linearly, then in an arc of approximately 130 about said vertical axis, and then linearly again,

said means comprising a rotatable crank, a shaft rotated thereby, a toothed gear wheel mounted on the end of said shaft, and gear teeth in the edge portion of said slide plate and meshing with said teeth of said gear wheel, said slide plate being operatively connected to said seat, also comprising a cam provided with slots, and pins cooperating with said slots, and said bottom plate being provided with guide grooves, and said slide plate being provided on its underside with pins seated in said guide grooves, whereby said slide plate, and said chair seat operatively connected thereto, may be forced to move in said plurality of directions when said rotatable crank is turned.

2. A chair according to claim 1, also including a neck support at the back, a Skullcap, means for fastening said support and cap to the chair, means for adjusting said support and cap in all three dimensions, an arcuate arm having means flexibly joining it to the chair and means for indicating the rotation axis position within the oral cavity, said support, cap and arm on the one hand, and said crank shaft and gear wheel on the other hand, all cooperating, whereby the chair accomplishes predetermined motion due to the driving elements whilst at the same time the patients head is constrained by the support and cap to described a motion precisely co-incidental in time and space with said motion of said chair, and whereby said arm cooperates whereby to externally indicate space co-ordinates within the oral cavity, said co-ordinates being determined by the joint cooperation of said driving elements and said constraining elements.

YRJo VELI PAATERO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 326,185 White Sept. 15, 1885 535,886 Brand Mar. 19, 1895 1,721,221 Jauregui July 16, 1929 2,123,927 Bell July 19, 1938 2,247,264 Van Derveer June 24, 1941 FOREIGN PATENTS N umber Country Date 207,015 Germany Feb. 18, 1909 

